Backlight module

Abstract

The invention discloses a backlight module which comprises a substrate, a plurality of first light-emitting elements, a plurality of second light-emitting elements and a reflecting layer. The plurality of first light-emitting elements and the plurality of second light-emitting elements are located on the substrate. The reflective layer has a first reflective region and a second reflective region. The plurality of first reflection structures are located in the first reflection region and surround the plurality of first light-emitting elements respectively. The plurality of second reflective structures are located in the second reflective region and surround the plurality of second light-emitting elements respectively. A thickness of each of the first reflective structures is greater than or equal to a thickness of each of the second reflective structures, and a thickness of at least one of the second reflective structures decreases away from the first reflective region.

Description

Technical Field

[0001] This invention relates to a backlight module. Background Technology

[0002] Backlight modules can be categorized into direct-lit and edge-lit types based on the location of the light source.

[0003] The light source typically used in direct-lit backlight modules mainly consists of a substrate and several light-emitting diodes (LEDs) arrayed at equal intervals on the substrate. The light generated by these LEDs can be further mixed by optical films to form a surface light source.

[0004] To meet brightness requirements (such as high-brightness areas on the dashboard or center console), existing direct-lit backlight modules for automobiles require a reflective structure around the array of light-emitting diodes on the substrate. Summary of the Invention

[0005] This invention provides a backlight module that can improve the brightness of a target bright area.

[0006] The backlight module of the present invention includes a substrate, a plurality of first light-emitting elements, a plurality of second light-emitting elements, and a reflective layer. The plurality of first light-emitting elements and the plurality of second light-emitting elements are located on the substrate, and the reflective layer has a first reflective region and a second reflective region. A plurality of first reflective structures are located in the first reflective regions and respectively surround the first light-emitting elements. A plurality of second reflective structures are located in the second reflective regions and respectively surround the second light-emitting elements. The thickness of each of the first reflective structures is greater than or equal to the thickness of each of the second reflective structures, and the thickness of at least one of the second reflective structures decreases with distance from the first reflective region.

[0007] An embodiment of the present invention provides an automotive direct-lit backlight module, including a substrate, a plurality of first light-emitting elements, a plurality of second light-emitting elements, and a reflective layer. The plurality of first light-emitting elements and the plurality of second light-emitting elements are located on the substrate, and the reflective layer has a first reflective region and a second reflective region. A plurality of first reflective structures are located in the first reflective regions and respectively surround the first light-emitting elements. A plurality of second reflective structures are located in the second reflective regions and respectively surround the second light-emitting elements. The thickness of each of the first reflective structures is greater than or equal to the thickness of each of the second reflective structures, and the thickness of at least one of the second reflective structures decreases with distance from the first reflective region. Attached Figure Description

[0008] Figure 1 This is an exploded view of a backlight module according to an embodiment of the present invention.

[0009] Figure 2 According to the present inventionFigure 1 A three-dimensional schematic diagram of the reflective layer is shown in the embodiment.

[0010] Figure 3A It is along Figure 2 The cross-sectional view is drawn with section line A-A'.

[0011] Figure 3B It is along Figure 2 The cross-sectional view is drawn with section line B-B'.

[0012] Figure 3C It is along Figure 2 The cross-sectional view is drawn with section line C-C'.

[0013] Figure 3D It is along Figure 2 The cross-sectional view is drawn with section line D-D'.

[0014] Figure 3E yes Figure 3D A magnified view of region E.

[0015] Figure 4A This is a top view schematic diagram illustrating the first and second reflective areas of the reflective layer according to an embodiment of the present invention.

[0016] Figure 4B This is a top view schematic diagram of the first and second reflective areas of the reflective layer according to an embodiment of the present invention.

[0017] Figure 5 This is a perspective schematic diagram of a substrate, a light-emitting element, and a reflective layer according to an embodiment of the present invention.

[0018] Figure 6 This is a three-dimensional schematic diagram of a reflective layer according to an embodiment of the present invention.

[0019] In the attached figures, the following labels are used:

[0020] 10: Backlight Module

[0021] 100:Substrate

[0022] 102a: First light-emitting element

[0023] 102b: Second light-emitting element

[0024] 200: Diffusion layer

[0025] 210: Diffuser plate

[0026] 300: Light control film

[0027] 310: Prism Sheet

[0028] E: Area

[0029] h: height

[0030] H1, H2: Thickness

[0031] L: Transition length

[0032] L1: Silver plating

[0033] L2: Polycarbonate material

[0034] p: Spacing

[0035] RA1: First Reflection Zone

[0036] RA2: Second Reflection Zone

[0037] RA3: Light diffusion region

[0038] RL, RL1, RL2, RL3, RL4: Reflective layers

[0039] RP1: First reflective structure

[0040] RP2: Second reflective structure

[0041] RP3: Third reflection structure

[0042] S1, S2: Sidewalls

[0043] TP1, TP2: Top Detailed Implementation

[0044] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0045] Figure 1 This is an exploded view of a backlight module 10 according to an embodiment of the present invention. Figure 2 for Figure 1 A three-dimensional schematic diagram of the reflective layer RL. Please refer to... Figure 1 and Figure 2 The backlight module 10 includes a substrate 100, a plurality of first light-emitting elements 102a, a plurality of second light-emitting elements 102b, and a reflective layer RL. The reflective layer RL has a first reflective region RA1 and a second reflective region RA2. Figure 1 and Figure 2 In the diagram, the first reflective area RA1 and the second reflective area RA2 are separated by a dashed line, and for clarity, the second reflective area RA2 is marked with a halftone dot.

[0046] A first light-emitting element 102a and a second light-emitting element 102b are disposed on a substrate 100 and overlap a first reflective region RA1 and a second reflective region RA2, respectively. The first light-emitting element 102a and the second light-emitting element 102b may include the same or different light-emitting diodes. In some embodiments, the substrate 100 may be a circuit board, which includes glass fiber epoxy resin (e.g., FR4 glass fiber board), but the present invention is not limited thereto.

[0047] A reflective layer RL is disposed on a substrate 100. In this embodiment, the reflective layer RL is separately formed from the substrate 100 and then bonded together. In other embodiments, the reflective layer RL is co-formed with the substrate 100. In this embodiment, a first reflective region RA1 surrounds a second reflective region RA2, but this disclosure is not limited thereto. In other embodiments, the number and position of the second reflective regions RA2 can be adjusted as needed. The reflective layer RL includes a plurality of first reflective structures RP1 and a plurality of second reflective structures RP2. The first reflective structures RP1 are located in the first reflective region RA1, and the second reflective structures RP2 are located in the second reflective region RA2.

[0048] When the reflective layer RL is bonded to the substrate 100, a plurality of first reflective structures RP1 surround a plurality of first light-emitting elements 102a, and a plurality of second reflective structures RP2 surround a plurality of second light-emitting elements 102b (e.g., ...). Figures 3A to 3C (As shown).

[0049] In this embodiment, each of the first reflective structures RP1 has a thickness H1 (see reference). Figure 3A Each of the second reflective structures RP2 has a thickness H2 (see reference). Figure 3B and Figure 3C The thickness H1 of each of the first reflective structures RP1 is, for example, equal, and the thickness H1 of each of the first reflective structures RP1 is greater than or equal to the thickness H2 of each of the second reflective structures RP2.

[0050] Please refer to Figure 3A Since the thickness H1 of the first reflective structures RP1 is the same, the top TP1 of all the first reflective structures RP1 lies on the same plane. In some embodiments, each first reflective structure RP1 includes a sidewall S1 surrounding the first light-emitting element 102a. The sidewall S1 includes, for example, a slope, and the inclination angle of the slope can be adjusted as needed. In some embodiments, the inclination degree of at least a portion of the sidewall S1 of the first reflective structures RP1 is adjustable. For example, the sidewall S1 of the first reflective structure RP1 can be rotated by a mechanism (e.g., a gear, a shaft, etc.).

[0051] Please refer to Figure 3B , 3CIn 3D, in the embodiments disclosed herein, the thickness H2 is not a constant. For example, multiple second reflective structures RP2 have more than one thickness H2. At least a portion of the second reflective structures RP2 have the same thickness H2. For example... Figure 3B As shown, the thickness H2 of the second reflective structures RP2 in the central region of the second reflective region RA2 is the same for all of them. The thickness H2 of at least one of the second reflective structures RP2 decreases with distance from the first reflective region RA1, as shown in the figure. Figure 3C and Figure 3D As shown.

[0052] Please refer to Figure 2 , Figure 3C and Figure 3D In some embodiments, the top TP2 of a portion of the second reflective structure RP2 is located on a different plane, and some portions of the second reflective structure RP2 have an inclined top TP2. In some embodiments, at least a portion of the second reflective structure RP2 closest to the first reflective area RA1 in the second reflective area RA2 has a thickness H2 that gradually decreases with distance from the first reflective area RA1, but this disclosure is not limited thereto. In some embodiments, more portions of the second reflective structure RP2 closest to the first reflective area RA1 have a gradually decreasing thickness H2. In some embodiments, each second reflective structure RP2 includes a sidewall S2 located around the second light-emitting element 102b, the sidewall S2 including, for example, a slope, and the inclination angle of the slope can be adjusted as needed. In some embodiments, the inclination degree of the sidewall S2 of at least a portion of the second reflective structure RP2 is adjustable. For example, the sidewall S2 of the second reflective structure RP2 can be rotated by a mechanism (e.g., a gear, a shaft, etc.).

[0053] exist Figure 3A In the middle, the first reflective structures RP1 are interconnected and form multiple T-shaped cross-sectional structures. Figure 3B In the middle, the second reflective structures RP2 are interconnected and form multiple T-shaped cross-sectional structures.

[0054] refer to Figure 3D The slope of the inclined top TP2 is equal to (maximum thickness H2 - minimum thickness H2) / transition length L, where the maximum thickness H2 is essentially equal to the thickness H1 of the first reflective structure RP1. In the second reflective region RA2, the transition length L is the horizontal length of the inclined top TP2. The magnitude of the transition length L can be determined based on the spacing p between any two adjacent light-emitting elements and the range of the target bright area.

[0055] In some embodiments, the spacing p is 4mm to 20mm, for example 12mm; the transition length L is 10mm to 30mm, for example 15mm; the thickness H1 of the first reflective structure RP1 is 3.2mm to 12mm, for example 4.8mm; and the minimum thickness H2 of the second reflective structure RP2 is 0.5mm to 4mm, for example 1.2mm. In embodiments of the present invention, the slope of the inclined top TP2 is between 0.2 and 0.8, for example 0.24. In some embodiments, the height h of the first light-emitting element 102a and the second light-emitting element 102b can fall within the range of 0.5mm to 2mm, for example 1.5mm. In some embodiments, the ratio H1 / h of the thickness H1 of the first reflective region RA1 to the height h of the first light-emitting element 102a falls within the range of 0.8 to 4, for example H1 / h is 1.37.

[0056] In one embodiment of the present invention, the height h of the first light-emitting element 102a and the second light-emitting element 102b can be the same, and the thickness H1 of the first reflective structure RP1 is greater than the height h of the first light-emitting element 102a, so as to guide large-angle light to the light-emitting surface. The thickness H2 of at least a portion of the second reflective structures RP2 (e.g., the thickness H2 of the second reflective structure RP2 near the central region of the second reflective area RA2) is less than the height h of the second light-emitting element 102b. Therefore, the light emitted by the second light-emitting element 102b can diffuse in the second reflective area RA2, thereby obtaining enhanced brightness. By making at least a portion of the second reflective structures RP2 include an inclined top TP2, the thickness H2 of the at least a portion of the second reflective structures RP2 gradually decreases as it moves away from the first reflective area. Therefore, it is possible to avoid a sudden change in thickness H2 that would cause a clear light-dark boundary line to appear between the portion of the display screen corresponding to the second reflective area RA2 and the portion corresponding to the second reflective area RA1.

[0057] In one embodiment of the present invention, the material of the reflective layer RL may include a high-reflectivity composite material, such as... Figure 3E As shown. The reflective layer RL comprises a polycarbonate (PC) material L2, and a silver plating layer L1 may be deposited on the polycarbonate material L2 to enhance the reflective effect, but the present invention is not limited thereto. In other embodiments, the reflective layer RL is made of a single reflective material.

[0058] In another embodiment of the present invention, the backlight module 10 may be provided with an optical film as needed, for example, in the present invention. Figure 1In this embodiment, a diffuser plate 210, a diffuser layer 200, a prism sheet 310, and a light control film 300 are sequentially disposed on the reflective layer RL of the backlight module 10. The light control film 300 may be, for example, a dual brightness enhancement film (DBEF), a liquid crystal film, or other suitable optical thin film.

[0059] Figure 4A and Figure 4B This is a top view of the first reflective region RA1 and the second reflective region RA2 of the reflective layer RL1 according to some embodiments of the present invention. Figure 4A and Figure 4B This diagram illustrates the distribution of the first reflective zone RA1 and the second reflective zone RA2, while omitting the detailed structure of the reflective layer RL1.

[0060] Please refer to Figure 4A The second reflective area RA2 can be located at the edge of the reflective layer RL1, but this invention is not limited thereto. The position of the second reflective area RA2 can be adjusted according to usage requirements.

[0061] exist Figure 4A In this invention, the second reflective area RA2 is circular, but the invention is not limited to this. The shape of the second reflective area RA2 can be determined according to the needs of the actual application, such as elliptical, polygonal, or other geometric shapes. In addition, the areas of the first reflective area RA1 and the second reflective area RA2 can also be determined according to the needs of the actual application.

[0062] exist Figure 4A In this invention, the number of second reflective regions RA2 is one, but this invention is not limited to this; the number of second reflective regions RA2 can be determined according to the needs of actual applications. For example, in... Figure 4B In one embodiment, the reflective layer RL2 includes two second reflective regions RA2, and a first reflective region RA1 surrounds the two second reflective regions RA2, but is not limited thereto. In other embodiments, the reflective layer RL2 includes three or more second reflective regions RA2. Additionally, in... Figure 4B In this embodiment, the two second reflective areas RA2 have different shapes, such as a circle and a square, respectively. The number, position, and shape of the second reflective areas RA2 can be determined according to the needs of the actual application.

[0063] Figure 5 This is a three-dimensional schematic diagram of a substrate, a light-emitting element, and a reflective layer according to an embodiment of the present invention. Figure 5 Implementation examples and Figure 1 , Figure 2 The same provisions as those in the embodiments will not be described here. Please refer to [link / reference]. Figure 5In addition to the first reflective region RA1 and the second reflective region RA2, the reflective layer RL3 also includes a light-diffusing region RA3. The thickness of the second reflective structure RP2 in the second reflective region RA2 decreases as it moves away from the first reflective region RA1 and closer to the light-diffusing region RA3; therefore, the thickness of the second reflective structure RP2 is not a constant. A third reflective structure RP3 is provided in the portion of the light-diffusing region RA3 closest to the second reflective region RA2, while no reflective structure is provided in the portion farther from the second reflective region RA2.

[0064] Therefore, when the reflective layer RL3 is bonded to the substrate 100, the third reflective region RA3 directly exposes the surface of the substrate 100 in areas where no reflective structure is provided. In the embodiment disclosed herein, a portion of the light-emitting element 102b is located in the light-diffusing region RA3. In the light-diffusing region RA3, a portion of the light-emitting element 102b is partially surrounded by the third reflective structure RP3, while the other portion of the light-emitting element 102b has no corresponding reflective structure around it.

[0065] In this embodiment, by setting the light diffusion region RA3, the deformation of the reflective layer RL3 caused by environmental vibration can be reduced, thereby improving long-term reliability.

[0066] Figure 6 This is a three-dimensional schematic diagram of a reflective layer RL4 according to an embodiment of the present invention. A first reflective region RA1 surrounds a second reflective region RA2. Figure 6 Implementation examples and Figures 1 to 3D The difference in the embodiments is that, Figure 6 In the second reflection zone RA2, each second reflection structure RP2 has a thickness H2 that gradually decreases as it moves away from the first reflection zone RA1.

[0067] The backlight module design of the present invention can be applied to automotive direct-lit backlight modules, such as direct-lit backlight modules for automotive displays that include dashboards and warning lights.

[0068] In summary, in the embodiments of the present invention, the thickness of each of the first reflective structures is greater than or equal to the thickness of each of the second reflective structures, and the thickness of at least one of the second reflective structures decreases with distance from the first reflective region. Therefore, the light emitted by the second light-emitting element can easily diffuse within the second reflective region, improving the problem of excessively rapid brightness decay in the boundary area of ​​the second reflective region, which leads to overly obvious light-dark boundaries.

[0069] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A backlight module, characterized in that, include: One substrate; Multiple first light-emitting elements and multiple second light-emitting elements are located on the substrate; as well as A reflective layer having a first reflective region and a second reflective region, and comprising: Multiple first reflective structures are located in the first reflective area and respectively surround the first light-emitting elements; as well as Multiple second reflective structures are located in the second reflective area and respectively surround the second light-emitting elements. The thickness of each of the first reflective structures is greater than or equal to the thickness of each of the second reflective structures, and the thickness of at least one of the second reflective structures decreases with distance from the first reflective region.

2. The backlight module as described in claim 1, characterized in that, The first reflective zone surrounds the second reflective zone.

3. The backlight module as described in claim 1, characterized in that, The second reflective zone is located at the edge of the reflective layer.

4. The backlight module as described in claim 1, characterized in that, The second reflective area can be a circular or polygonal region.

5. The backlight module as described in claim 1, characterized in that, The number of these second reflective zones is greater than one.

6. The backlight module as described in claim 1, characterized in that, At least a portion of these second reflective structures have the same thickness.

7. The backlight module as described in claim 1, characterized in that, These second reflective structures are interconnected and form multiple T-shaped cross-sectional structures.

8. The backlight module as described in claim 1, characterized in that, These first reflective structures are interconnected and form multiple T-shaped cross-sectional structures.

9. The backlight module as described in claim 1, characterized in that, The reflective layer includes polycarbonate and a silver plating layer.

10. The backlight module as described in claim 1, characterized in that, The inclination of at least some of the sidewalls of the first reflective structures and / or at least some of the sidewalls of the second reflective structures is adjustable.

11. The backlight module as described in claim 1, characterized in that, At least one of these second reflective structures has a sloping top.

12. A direct-lit backlight module for automotive applications, characterized in that, include: One substrate; Multiple first light-emitting elements and multiple second light-emitting elements are located on the substrate; as well as A reflective layer having a first reflective region and a second reflective region, and comprising: Multiple first reflective structures are located in the first reflective area and respectively surround the first light-emitting elements; as well as A plurality of second reflective structures are located in the second reflective region and surround the second light-emitting elements, wherein the thickness of each of the first reflective structures is greater than or equal to the thickness of each of the second reflective structures, and the thickness of at least one of the second reflective structures decreases as it moves away from the first reflective region.

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